Thermomicrophonic firing device for submerged mines



J. J. DUFFIE THERMOMICROPHONIC FIRING DEVICE FOR SUBMERGED MINES Filed Aug. 9. 1917 2 Sheets-Sheet 1 I 1,538,315 J. J. DUFFIE' THERMOMIGROPHONIC FIRING DEVICE FOR SUBMEKGED Mil WES Filed Au 9. 1917 2 Sheets-Sheet 2 "61 ten,

vvent the vibrations from the,

Patented May 19, 1925.

issans Parent orricn.

JOHN J. DUFFIE, OF BERKELEY, CALIFORNIA, ASSIGNOR TO GOVERNMENT OF THE UNITED STATES.

THERMOMICROPHONIC FIRING- DEVICE FOR SUBMERGED MINES.

Application flied August 9, 1917. Serial No. 185,245.

1 '0 all 1127mm it may concern:

Be it known that I, JOHN J. DUFFIE, a citizen of the United States, residing at Berkeley, in the county of Alameda and State of California, have invented certain new and useful Improvements in Thermoniicroplionic Firing Devices for Submerged Mines, of which the following is a specification.

This invention relates to a thermo-iiiicrophonic firing device for submerged mines.

The primary object of this invention is to create the explosion of a sul'imerged mine through the medium of the. sound waves emanating from a submarine or other vessel in the vicinity of the mine.

An explosive mine when positioned in the sea presents a small target to be struck by a submarine. In fact, afield of mines thickly anchored often fails 'to provide an effective barrier for enemy vessels. Destructive nets and cable barriers are placed in position under great dil'liculty, they always require considerable time for adjustment,

and their points of location are easily discovered by the enemy.

Through the use of my firing device, the

foregoing; objections or difliculties are over come. First, for the reason that I create a danger field or zone of'a given diameter radiating from the mine. Second, 'tor the reason that by placing a series ofthermo inici-ophonic operated mines at certain distances apart so that the danger fields or,

zones are contiguous or slightly interlap, thereby creating an absolute barrier against the passage of enemy vessels.

My tliermo-microphonic system of firing mines is to be adjusted previously to 'setting the mine, so that no extra time is consumed when placing the mine in an opera tive position. Further, by using the timing device shown in my pending application, filed July 24, 1917, Serial No. 182,481, in

operative conjunction with my present firing device, the former will-positively preplanting ship from creating an explosion of the mine during any predetermined or prescribed length of time. 3

Vith the foregoing and other objects in view that will appear. as the nature of the invention is better understood the same consists in the novel features of construction, combination aiulvarraiigement of parts illustrated in the drawings and more particularly pointed out in the appended claims.

In the accompanying drawings, in which like parts are designated by like characters throughout the several views,

Figure 1 is a detail fragmentary sectional view of a submerged mine illustrating the application of my thernio-microphonic liring device;

Figure 2 is a diagrammatic view of the firing device;

Figure 3 is a detail central longitudinal section of the micri'iphonic receiver;

Figure 4 is a vertical transverse section taken on the line 41 of Figure 3. looking in the direction indicated by the arrows;

Figure 5 is an elevation of the circuit closer with the mercurial container and associated parts shown in section, and

Figure 6 is an edge view of the circuit closer looking at right angles to Figure 5.

Referring to the drawings for a more particular description of the invention, and which drawings are for illustrative purposes only and are, therefore, not drawn to scale, 1 indicates a mine, 2 the microphonic receiver, 3 the circuit closer, 4 the solenoid magnet which projects the firing pin, 5 the firing pin and (3 the detonating cap of the paratus.

The microphonicreceiver 2 of the firing device may be supported in operative position on or in the'mine, in any suitable manner. For example, a hollow cylindrical interiorly threaded supporting member 9 may be bolted, as at 10, to the top wall 11 of the mine shell or casing with its inner end projecting into the compartment or space 7' and the cylindrical body member, as 12, of the inicroplionic receiver 2, exteriorly threaded, as at 13, for screw-threaded engagement with said member 9. As shown in Figure 1, the inner end of the body mcinber 12 of themicroplionic receiver may pi oject somewhat beyond the adjacent or corresponding end of the supporting member 9, to provide for the application of the washer and lock nut 14 and '15, respcc-v tively, whereby said body member-12 may be securely held in place. However, in actual practice any other suitable or equivalent means may be utilized to support the microphonic receiver in position on the mine;

The circuit closer 3 which is situated in the compartment or space 7 at the top of the mine, adjacent the microphonic receiver, is mounted on the upright approximately rectangular oblong base 16. Specifically, the circuit closer comprises a hollow cylindrical mercurial container 17 gradually tapered at both ends and supported in a vertical position on the base by the keeper rings 18 and 19 of the bearing brackets 20, fastened by screws 21 or other equivalent means to the base 16. The upper endof the mercurial container is provided with a hollow stem 22 of reduced diameter, the upper end of which is received by the packing gland 23 to provide a close fitting joint and cushion for said end of the stem. An electrode 24 extends into the upper end of the stem 22 of the mercurial container and is carried by an insulated arm 25 extending laterally or at right angles from the upper end of the supporting bar 26. Said electrode may be adjusted in a vertical plane either up or down by means of the aforesaid bar 26, which is slidably mounted in the bearing lugs or brackets 27 of the base, and is retained in adjusted position by the screw 28 or other equivalent means.

A resistance coil 29 closely surrounds or encircles the body portion of the mercurial container 17, the lower end'or bottom of which is electrically connected with one side of the battery 30 by the conductor 31. The upper end or top of the resistance coil is connected with a second conductor 32, which cooperates with other parts hereinafter described, in closing the circuit to the other side of the battery, when the sound waves generated by an approaching submarine or other enemy vessel within the field or area of influence on the microphonic diaphragm are transmitted through the medium of the water to the diaphragm 33 of the microphonic receiver. The diaphragm 33, which in the present illustration is in the form of a relatively thin disc, and is arranged in the outer end of the cylindrical body member 12 of the microphonic receiver, is insulated from said body member 12 by the insulating ring 34, and is provided at the center with a horizontal inwardly extending arm 35 to which is connected an oscillating or vibratory arm 36. the upper end of which works between and is adapted to alternately 'engage or contact with flanges 37 formed at opposite ends of a spool 38, equipped with a threaded stem 39, which passes through a corresponding transverse opening in the cross bar 40 and is hefd in place by the fastening nut 41. 1 As shown, the inner end of the stem 39 of the spool 38 is connect-ed, as at a, with the conductor 32. It will also be noted that the lower end of the oscillating arm 36 is pivoted to the bearing post 43 secured to and insulated from the cross bar 40 by a screw threaded insulating plug 44.

In practice, when a submarine or other enemy vessel comes within the circle or area of influence upon the microphonic diaphragm 33, the sound vibrations generated by and emanating from said vessel are transmitted through the medium of the water to and are picked up by the diaphragm 33 of the microphonic receiver which creates a vibratory action of the"diaphragm, which, in turn, imparts an oscillating or vibratory movement to the arm 36, the upper or free end of which alternately contacts with the flanges 37 of the spool 38, as before stated. Under these conditions, as the submarine gradually approaches the mine, the electrical pulsations from the battery 30 to the resistance coil 29 gradually raise the temperature of the mercury in the thermostatic con tainer 17, thereby causing it to expand and slowly ascend in the stem 22. of said container until it reaches and comes into contact with the lower end of the electrode 24.

The circuit from theba-ttery 42 through the solenoid magnet 4 is then closed, thereby causing the firing pin 5 to strike or impact the detonating cap 6 and create an explosion of the mine. The mercury in the container 17 is placed in electrical circuit with one side of the battery by the conductor 45. The electrode 24 is connected with the solenoid magnet 4 by the'conductor 46, and thesolenoid magnet is connected with the other side of the battery by the conductor 47. The outer end of the microphonic receiver is preferably closed by the closure cap 48.

If desired, the microphone may be of any type other than that illustrated, such, for

instance, as the vibratory metal ring type, etc. Also, if desired, the diaphragm of the microphonic receiver may be tuned in harmonic accord with the dominant tone created by the submarine motor.

A graduated indicator 50 is adjustably mounted on the base 16 to compensate for the varying temperatures in the different seas or other bodies of water in which the mines may be placed. The lower end of the llO plate 50 is adjusted to the top of the mercury column in the tube 22, the height of said column of course varying with the temperature of the water in which the mine is immersed. The electrode 24 is then adjusted with reference to the scale, to leave between its lower end and the top of the mercury column the number of spaces or graduations hrough which said column will expand under a given rise of temperature. In this way the time required to establish electrical connection through the mercury and through coil 4, battery 42 and intermediate conductors, can be accurately determined. These adjustments are made with reference to the lll,

, broadly a new'device.

' destructivity of the mine.

average speed of submarines, and wi th a view to allowing time sufiicient for the craft after entering the zone of receptivity of the microphone to approach within the area of From the foregoing description taken in connection with the drawings, it is thonght that the construction, operationand advan tages of this invention will be readily understood without requiring a moreextended ex- I planation. Various changes in the form,

proportions and minor details of construction may be resorted to-Without departing from the principles or sacrificing any of'the advantages of this invention as defined in the appended claims.

I am aware that it has been proposed to efl'ect the transmission of signals, and to operate or control electrical'deviees at a dis tance, by transmitting from a distant station on land or afloat, predetermined soundwaves to act upon a microphonic device at the distant point, through which the signals are given -or the electrical devices are brought into action. I am further aware that a thermostatic circuit closer is not So far as I am aware, however, no one has ever before produced or proposed a mine of the submerged class which should be automatically detonated or exploded by devices brought into action through souml-waves emanating from a vessel entering a predetermined zone about the mine. \Vhile various of the elementsemployed by me are old per se,the structure described and the application of the elements recited are believed to be new, and

they produce a result not heretofore attained so far as I am aware.

The terms submerged mine and mine of the submerged class are used throughout this specification and inthe claims to identify the general typeor class of mines to which the invention pertains, and of course mean mines whichpwhenplaced for use, are to be submerged. ,Thcy are to be read with this understanding.

Automobile or locomotive torpedoes are not comprehended within the phrase mine of the submerged class or any similar language used in this description and cla-ims.

I claim:

1. A mine of the submerged'class containing within itself a source of electric energy, a circuit including js'aid source, a circuit closer, and heat-actuated meansfor completing the circuit through said closer; and means for exploding said mine adapted to be brought into action through the closure of said circuit.

2. A submerged mine comprising a. shell or container; an explosive charge therein; detonating means for exploding said charge, including a movable firing-pin and electromagnetic means for actuating sa'id pin: a

source of electric energy; acircuit containing said source, the electromagnet of the detonating device, and a normally open circuit closer adaptedto close on a rise of temperature; and a second electric circuit including a source of electric energy, an electric heater'inproximity to the circuit-closer of the first-nan'ied circuit, and a normally open circuit-closeradapted to be brought into action through a sound-responsive de vice carriedby the mine.

3. A mineoi' the submerged class, comprising a she'llor container provided with a microphonic receiver, a source of electric ene rgy, and aci'rcuit includihgsaid source, the receiver, andamake-and-break device actuated by there'cei ver and servingalternately to close and openlsaid circuit; an explosive charge a 'se' 'bud.circuit-closer responsive to and rendered operative by the action of the receiver; a "second source of electric energy;

means for-firing the explosive charge; and a circuit including said second source of energy, thesecondcircuit-eloser, and the means for firing the explosive charge, the movable element of: the second circuit-closer being adapted toe-return automatically to normal position if thesound-responsive device ceas'e plosive charge; a source of electric energy for actuating said firing device; and a circuit including said source of energy, the firing device, and a second circuit-closer, said second circuit-closer being under the control of and brought into action by the sound-responsive device and its circuit-closer if the action of the sound-responsive device continue a sufii'cientl'ength of time but resuming its normal condition or adjustment if the action- 0f the sound-responsive device ceasebefore: said circuit is completed.

5. A mine ofthe submerged class, comprising ashellwor container; an explosive charge within said shell or container; 2. detonating device adapted to be brought into action through a rise of temperature; a microphonic receiver jresponsive to sound- Waves; and a heatingfdevicejbrought into action through vibrationof the microphomc receiver incident to reception of soundwavcs, and serving'when so energized to bring into action the detonating device.

6. A mine of the submerged class containing within itself an explosive charge; electrical means for exploding said charge; a

source of electric energy; a circuit including said source of energy, exploding device, and a thermostatic circuit-closer; an electric heater for said thermostatic circuit-closer; a source of electric energy; a microphonic receiver and a make-and-break device actuated thereb and a circuit including said source of energy, receiver, make-and-break device, and heater.

7. A mine of the submerged class comprising as a unitary and self-contained structure, a shell or container; an explosive charge; a detonating device for firing said charge; and means responsive to sound- Waves for bringing into action said detonating device, said means including a circuit closer tending to close gradually the detonating circuit as the sound-responsive device continues to function but to resume its normal condition or adjustment if the soundresponsive device cease to function before the detonating circuit is completed.

8. A mine of the submerged class comprising within itself and as a unitary structure, a shell or container; I an explosive charge contained therein; an electric detonating device; a source of electric energy for said device; an electric circuit including said source, detonating device, and a gradually-acting circuit closer; a sound-responsive device; a source of energy therefor; a make-and-brcak device actuated by said sound-responsive device; and a circuit including the sound-responsive device, the make-and-break device, and the circuit closer of the detonating circuit; whereby sound Waves acting upon the sound-responsive device are caused in turn to move one element of the detonating circuit gradually toward the companion element thereof and .if the action of the sound-responsive device continue for a predetermined length of time, to complete the detonatingcircuit and fire the explosive charge. i

9. A mine of the submerged class comprising Within itself and as a unitary structure, va shell or container; an explosive charge; a sound-responsive device; a source of electric energy; and a detonating device in circuit with said source of energy for exploding said charge, said circuit including also a circuit closer having one of its contact elements movable toward the other through the continuing operation of the sound-responsive device but adapted to return automatically to normal position or adjustment upon the cessation of such operation occurring prior to completion of the detonating circuit.

10. A self-contained mine of the submerged class, I comprising an explosive" charge; electrical means for causing explosion of said charge; and means responsive to sound waves, serving to actuate a circuit closer for completing the circuit of and thus bringing into action said explosion producing device if the sound-responsive device continue in action a sufficient time, but torestore the circuit closer to normal position or adjustment if such ac: tion cease before completion of the circuit.

11. A. mine of the submerged class' comprising within itself a destructive charge; a discharging device therefor; a sound-responsive device exposed to sound Waves proceeding through the medium in which the mine is located; and connections between .the sound-responsive device and the discharging device, including a thermostatic circuit closer capable of being set to close the firing circuit only after a predetermined period of operation of the sound-responsive device.

'12. In combination with and as parts of an explosive mine of the submerged class, a discharging means therefor; a sound-rcs onsive device and means im'crmediate the 7 souinl-responsive device and the discharging means, and operable through continuing action of the souml-responsive device to complete in a predetermined period of time the connection between the sound-responsive means and the discharging means.

13. In combination with and as parts of sive device, and a timed connecting device interposed between the sound-responsive device and the discharging device; whereby the discharging device is brought into action by the action of the sound-responsive device continued for a predetermined period of time.

15. A mine of the submerged class comprising Within itself a destructive charge;

a discharging device therefor; a sound-re sponsive device exposed to sound waves proceeding through the medium in which the mine is located; and connections between the sound-responsive device and the dis charging device, including a tl'iermostatic circuit closer capable of being set to close.

the firing circuit only after a predetermined minimum period of operation of the soundresponsive device.

16. In combination with an explosive mine of the submerged class, a sound-rcsponsive device; an electric circuit: a'minedischarging device included in said circuit and operable through elevation of temperature; a circuit closer for said circuit; and

means controlled by the sound-responsive device for actuating said circuit closer, and thereby effecting the requisite elevation of temperature.

17. In combination with an explosive mine and a discharging device therefor; asoundresponsive device; and a thermostatic device interposed between the discharging device and the sound-responsive device, and operable by the latter to bring the discharging device into action.

18. In combination with an explosive mine, discharging means therefor; a soundresponsive device; and normally interrupted connections between the sound-responsive device and the discharging means, including a gradually moving member under control of the sound-responsive device, for efiect- I mg a gradual or timed completion of the connections between the sound-responsive device and the discharging means, and ca- JOHN J. DUFFIE. 

